Okay, so I have two bettas at this point.. Nettlestung, my halfmoon male is in a 10gal to himself, and Starchaser, my king plakat, is in a 5gal to himself. The more I got thinking, I realized I should probably switch the two of them. Nettle swims around a bit, but doesn't really utilize the entire tank (likely because of his fins).

Do you think I should switch them? If I do, should I just give both tanks a good gravel vac/water change before moving them?